Rule

The rule of disparity states that with the progress of evolution some fauceirs remain at a lower stage of evolution. They not only remain at that stage even new fauceirs evolve at a lower stage, always providing a whole spectrum of fauceirs at different stages of evolution.

Rational

The higher level fauceirs are composed of level fauceirs, so lower level fauceirs play an essential role for higher level fauceir's proper function. If they are no longer necessary for that they may remain in ecological niche or go extinct.

Examples

Although biological and social fauceirs evolved on this planet physical fauceirs remain the majority.

Although higher animals and plants evolved, bacteria, and fungi still exist.

Although height evolved social systems exist on this planet, some people still live in hunter-gatherer societies or slavery or feudalism.

Although advanced monotheistic religions exist, many people still adhere to satanism , superstition or other more primitive forms of natural religion.

Although human behavior can be controlled by rational thinking, most of our actions are reflexive, subconsciously or ideologically determined.